The present invention relates to an actuator of the plunger type usable in a highly pressurized fluid, e.g. on board a submarine craft able to work at great depths.
Numerous submarine vessels and equipments require the use of mechanically acting actuators either for transmitting a force (releasing ballast, grasping objects, etc.) or for carrying out locking or unlocking. Most of these systems are based on increasing the forces with the aid of levers moved by mechanical systems or hydraulic systems. In the latter case, the craft has to carry a hydraulic generator, These means have to be used at widely varying immersion levels, e.g. at depths between 0 and 11,000 metres when used underwater, or in a liquid which can contain solid suspensions. The main problem is to maintain the optimum reliability level (particularly in the case of ballast release), so that the design of such actuators is far from easy.